Figure 6. Orientation selectivity of dendrites within a dendritic bundle.

(a) Apical dendrites and cell bodies of OGB1-AM loaded layer 5 neurons. Scale bars 100 μm. (b) A x–y section of apical dendrites of OGB1 loaded layer 5 neurons. Dendritic bundles can be clearly visible. Scale bars, 10 μm. (c) To quantify the visual selectivity of dendrites, individual dendrites are detected, and dendritic bundles are identified using Voronoi tessellation and the nearest neighbour method (see Methods). The black circles show dendrites, and each dendritic bundle is separated by black lines. The red dotted rectangle corresponds to the white dotted rectangle in d and is magnified in e. Scale bars, 10 μm. (d) A three-dimensional orientation map of dendrites. Every pixel is coloured according to the response to the orientation stimuli (hue: preferred orientation; lightness: response magnitude; saturation: gOSI). Each dendrite shows single orientation selectivity along the entire length in the image. Volume size is 128 μm (x) × 64 μm (y) × 100 μm (z). (e) A x–y section of orientation map of dendrites selected from a volume in d and the area corresponding to the white dotted rectangle in d is magnified. Each dendritic bundle is separated by white lines. Dendrites in the same bundle have different orientation preferences. Scale bars, 10 μm. (f) Averaged signal changes in dendrites #1–4 (the number is shown in e) in response to the orientation stimuli. Grey shaded: stimulation periods, white: blank periods. The angle of orientation presented during each stimulation period is illustrated at the bottom.